[mpich-discuss] MPI_Alloc_mem: optimized memory usage

[Dorian Krause]

Rajeev Thakur wrote:
> Yes, it is useful for MPI-2 one-sided communication, but perhaps less useful
> for send-recv.
>
> Rajeev 
>
>   

What would be the advantage on commodity hardware? Can we do better than 
malloc if the Interconnect doesn't support something like RDMA?

Thanks,
Dorian

>> -----Original Message-----
>> From: mpich-discuss-bounces at mcs.anl.gov 
>> [mailto:mpich-discuss-bounces at mcs.anl.gov] On Behalf Of James S Perrin
>> Sent: Monday, November 10, 2008 5:24 AM
>> To: mpich-discuss at mcs.anl.gov
>> Subject: Re: [mpich-discuss] MPI_Alloc_mem: optimized memory usage
>>
>> Thanks for the info Rajeev. Would this be something worth 
>> looking at in 
>> future releases in the nemesis channel as we run more systems 
>> with more 
>> and more cores per node?
>>
>> Regards
>> James
>>
>> Rajeev Thakur wrote:
>>     
>>> In the sshm channel (scalable shared memory), which is now 
>>>       
>> deprecated,
>>     
>>> Alloc_mem allocated shared memory for use in one-sided 
>>>       
>> communication. I
>>     
>>> believe in other cases at present, Alloc_mem just calls malloc.
>>>
>>> Rajeev 
>>>
>>>       
>>>> -----Original Message-----
>>>> From: mpich-discuss-bounces at mcs.anl.gov 
>>>> [mailto:mpich-discuss-bounces at mcs.anl.gov] On Behalf Of 
>>>>         
>> James S Perrin
>>     
>>>> Sent: Friday, November 07, 2008 11:55 AM
>>>> To: mpich
>>>> Subject: [mpich-discuss] MPI_Alloc_mem: optimized memory usage
>>>>
>>>> Hi,
>>>> 	Are MPICH2 calls optimized for SMP/multi-core 
>>>> architectures if I 
>>>> allocate buffers using MPI_Alloc_mem()? I was reading the in 
>>>> the MPI2.1 
>>>> spec that MPI_Alloc_mem can be implemented to take advantage 
>>>> of shared 
>>>> memory pools when available meaning I can keep my code 
>>>>         
>> portable and 
>>     
>>>> clean. Presumably this would only be available in ch3:ssm 
>>>>         
>> and nemesis 
>>     
>>>> channels.
>>>>
>>>> Regards
>>>> James
>>>>         
>> -- 
>> --------------------------------------------------------------
>> ----------
>>    James S. Perrin
>>    Visualization
>>
>>    Research Computing Services
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>>   "The test of intellect is the refusal to belabour the obvious"
>>   - Alfred Bester
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>>